I don't really think that the previous answers have addressed your question because both of your youtube examples are
specifically explaining how to work out
pot odds
That is, these clips are describing how to calculate the 'ratio of the chips in the pot (after you call) to the number of chips you will have to put in'
It is very important to be able to work this out. These you tube clips you have linked to are ok, they do explain how to calculate this, and you should probably study them until you can predict the answers to his examples long before he has laboriously worked them through.
As I said these videos only address this specific problem, but there is more that you will need to know before you can continue
Once you know your
pot odds, you can compare these to the 'odds that you will make the best hand' and only then will you know if you should make the call.
For example if you are on a flush draw (perhaps you have 2 hearts including the Ace and there are 2 hearts on the board) there are 9 hearts left in the deck (or already dealt) that you haven't seen yet.
With this info you can calculate that you have approx. 19% (or 1:4) chance to hit your card and make the winning hand.
So will require pot odds of better than 19% to make this a profitable call (in the long run)
Calculating the likelihood of making your winning hand is what the other posters are referring to when they say
Number of outs (9) x2 (18) +1 (19%)
